Compressor-controlling mechanism



Nov. 20, 1928.

F. D. HOLDSWORTH COMPRESSOR CONTROLLING MECHANISM Filed Jan. 11, 1925 HI FINE- O Patented Nov. 20, 1928.

UNITED STATES PATENT-0F FICE."

MACHINERY COMPANY, A. CORPORATION 01 MASSACHUSETTS.

COMPRESSOR-CONTROLLING MECEANTSM.

Application fil ed January 11, 1926. Serial No. 80,589."

This invention relates to controlling mechanisms and more particularly to controlling mechanisms for internal combustion engines employed in the driving of air compressors or other pumping devices. A

It is highly desirable in the driving of air compressors by internal combustion engines that during periods when no air is required the compressor be unloaded without stopping the engine, that during such periods of unloaded operation the engine be throttled in such a manner as to reduce its speed, and that when the com ressor is to be reloaded the engine be brought up to its full speed before the load is again thrown upon the compressor.

Among the objects of the present invention is the provision of an improved controlling mechanism for a compressor driving engine operative to efi'ect control of the latter in the manner described. Another object of the invention is to provide an improved internal combustion engine driven fluid umping system having improved contro ling means.

Other objects and advantages of the invention will subsequently appear.

In the accompanying scale taken. on the same plane as the sectioned portions of Fig. 2 showing details of controllin valve construction.

In the drawings 1 indicates generally a wheel mounted portable compressor outfit comprising a wheeled truck 1 supporting an internal combustion engine 2 suitably con}. I

nected in driving relation to an air compressor 3-which discharges the air compressed through a line 4 to a receiver 5. The compressor 3 is provided with appropriate unloading mechanism operated by pressure fluid delivered throu h a line 6. Unloading and reloading are e ected in accoradnce with the variations in receiver pressure acting through drawings in which for pur oses of illustration one embodiment a pilot valve 7. This pilot valve may be of anywell known construction and is designed line 8 to atmosphere; The variations in pressure in the line 8 are communicated to the line Bandto the'compressor unloading'mechamsm in a manner which will shortly appear.

The intake manifold of the compressor driving en ine 2 has connected thereto an air line 11 an a carburetor 12, the combustible mixture being conducted by a verticall extendm pipe 13 to the intake manifol A butter y valve 14 is mounted upon a shaft 15 in the intake line-'13 and is normally maintained in full open position by a coiledspring 16. The positions of maximum and minimum opening of the valve 14 may be adjust-- ably controlled by screws 17 and 18 mounted on arms 19 secured in rigid relation to the valve carrying shaft, but other control means is provided as later described. An arm 20 similarly secured to the shaft controls the opening of the valve in a manner later described.

Upon a sleeve memberj21 secured at the junction between the air supply connection 11 and the base of the carburetor 12 and trav-. ersed by the air supply opening is formed a bracket portion 22 supporting a vertical controlling mechanism generally designated 23.- The latter comprises mechanism generally designated 24 for controlling the communications between the lines 6 and 8, and mechanism generally designated 25 for controlling the position of the valve 14. Mechanism 25 comprises a cylinder member '26 externally threaded and held by nuts 27 upon the exterior thereof in rigid relation to the bracket portion 22. Reciprocable within the cylinder is a piston 28 into whose interior a rod 29 extends, the rod' abutting against the bottom end of the interior of the piston and carryin an abutment members 30 which is engage by a sprin 31 whose other end engages a guide mem er 32 for the rod 29. A look nut 32 serves to lock the member 32. Relative.

of closure of valve 14 as will later be evi cut. The line 8'opens into the bottom of the chainmentioned that this valve may also be conber 33 of the cylinder 26 and op osite the point of communication, 34, of the 1ne'8 1s a connection 35 to which a- U-shaped pipe 36 s connected at one end. The other end of th s pipe opens into a valve casing 38 which is secured at its upper end to the lower end of the cylinder 26. The valve casing 38 is prov ded at its opposite ends with a pair of alined chambers 39 and 40 and intermediate these chambers with a central chamber 41 with which the connection 36 communicates. The chamber 41 communicates through openings 42 and 43 respectively with the chambers 39 and 40. A check valve 44 normally held 1n closed position by a spring 45 cooperates with a seat 46 surrounding the opening 43 and 1s provided with a stem 47 which extends through the opening 42 into the chamber 39 when the valve is closed. A polygonal plunger 48 is loosely slidable in the chamber 39 and terminates in a reduced ste'm 49 projecting into engagementwith the plston 28 when the latter is in bottom position. The line 6 communicates at 50 with the chamber 40. The compression of the spring 45 may be adjusted by an adjustable perforated threaded follower 51. Rod 29 has an adjustable abutment member 52 thereon engagingarm 20 and ad ustable to control the full open positions of valve 14. Assume that the engine is operating the compressor and that the latter is loaded. The parts will then occupy the po sition shown in Fig. 2 and the valve 14 will be approximately wide open. It may be trolled if desired by a speed governor, the control by the speed governor being independent of that by the air controlled mechanism described above. Let it now be assumed that the air pressure within the receiver builds up to such an extent that the pilot valve 7 opens, admitting'pressure to the line 8. The effect of the admission of air to this line will be two-fold. In the first place the air will pass to the lower end of the piston 28, through the connection 36, past the valve 44, and into line 6, and unload the compressor. The pressure will alsoact upon tllGPlSllOIl 28 to force the latter upwardly, moving the plunger 29 and thereby the arm 20 to close the throttle valve 14 to the extent necessary to effect the running of the engine 2 at reduced speed with the compressor unloaded. When the pressure in the line 6 approaches equality to that in line 8 the valve 44 will be closed by the s ring 45 and remain closed except as it may e o ened by air pressure should leakage cause re notion in ressure in the line 6 to a sulficient degree efore reloading occurs. When the compressor discharge pressure reaches the predetermined desired minimum for which the pilot valve 7 is set, the latter will close olf communication between the receiver and line 8 and will vent the latter to atmosphere. As a result the pressure in the I line 8'and so in the cylinder 26 will begin to I fall and with the falling of this air pressure the spring 31 will force the piston 28 and also 1 the rod 29 downwardly, permitting the lever 20 to move downwardly, opening the throttle 14 and speeding up the driving engine 2. Only as the engine throttle opens fully again will the piston 28 engage the stem 49 and force open the valve 44 which has been acting as a check valve and preventing the flow of the air maintaining the compressor unloaded back through the passage 43, connection 36, and pipe 8 to the atmosphere. opening of the valve 44, however, the pressure whichhas been maintaining the comimity to the parts controlled thereby.

While I have in this application s ecifical- 1y described one embodiment whic my invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with a compressor and an internal combustion driving engine therefor, of controlling means for said compressor and for said engine comprising a cylinder adjustable in length, a piston therein, a plunger movable with said piston, a throttle for said engine having a controlling element engageable by said plunger, and means coaxiallyl arran ed with said piston and actuated t ereby or controlling the condition of said compressor.

2. The combination with a compressor and an internal combustion driving engine therefor, said engine havin a combustible mix ture supply line extending vertically, of controlling means for said compressor and for said engine comprising a cylinder disposed parallel to said supply line, a piston therein, a

lunger movable with said piston, a throttle or said engine in said supply line having a controlling element engageable by said plunger, and means coaxially arranged with said piston and actuated thereby for controlling the condition of said compressor.

3. The combination with a compressor and With the an internal combustion driving engine therefor, said engine having a combustible mixture supply line having a substantially straight portion provided with a butterfly valve, of controlling means for said compressor and for said engine comprising a cylinder disposed parallel to said supply line, a piston therein,'a plunger movable with said piston and operative to control the position of said 10 butterfly valve, and means coaxially arranged with said piston and actuated thereby for controlling the condition of said compressor. 4. The combination with a compressor and a prime mover for driving the same, of pressure fluid operated unloading means for the compressor, a control for the prime mover including a cylinder and piston, the end of said cylinder and said piston cooperating to leave a space when the piston is at the end of its stroke, and means for controlling said unloading means including a pilot valve controlled passage communicating with said space, a check valve device axially alined with said cylinder, said check valve being positively opened by the last of the movement of said piston, said check valve device providing a passage leading from the valve side of said check valve to said unloading, means, and a passage leading to the space at the end of said cylinderfrom the other side of said check valve, said passage being independent of the clearance surrounding the stem of the check valve.

In testimony whereof I aflix my signature.

FRED D. HOLDSWORTH. 

